This invention relates to an all-around observation device for detecting a field of view having a large solid angle by at least one detector having a two-dimensional arrangement of detector elements.
Such an all-around observation device shall observe, with high spatial resolution, a large field of view, which is larger than half-space. For example, the all-around observation device shall continually observe a region of 360.degree. in azimuth and of -30.degree. to +90.degree. in elevation. This can only be realized by scanning, i.e. in a manner, in which the individual field of view sectors are detected consecutively. This, however, results in two requirements: The scanning has to be effected with sufficently high repetitive frequency. Thus, the field of view has to be scanned in a time as short as possible. Furthermore, however, the detector has to be exposed to each field of view sector for a sufficiently long time.
This problem cannot be solved by using a rigid system of imaging optical system and detector, which rigid system is consecutively directed to individual field of view sectors. A motion over 360.degree. alone would require twelve to sixteen single images when using conventional IR-matrix detectors. To this the elevation steps must be added. Using a scanning procedure similar to Mercator's projection, approximately six hundered images per second have to be made. It is not possible to swing and position the optical system and the detector at this frequency. This is also true in the case when two detectors are used and the frequency can be reduced by half.
Continuous movement of such a rigid system would lead to movement blur to an extent, which is not acceptable.